June 1900.] BOTANICAL SOCIETY OF EDINBURGH 321 



or the entire buds, are lieated to the boiling-point 

 in water it coagulates, forming either a single greyish 

 finely granular mass, enclosing the starch grains and 

 filling the cell, or two or three small, rounded, drop- 

 like aoffresations among which the starch grains are 

 distributed. It is coagulated in a similar manner in buds 

 which have been preserved in alcohol, as well as in thick 

 sections treated with mercuric chloride, chromic acid, or 

 Millon's reagent, with the last of which, however, it only 

 gives a greyish yellow tint, though with nitric acid and 

 ammonia a very marked xanthoproteic reaction is obtained. 

 We may therefore conclude that the reserve proteid 

 takes in this case the form of a fluid albumin similar to 

 that described by Bokorny (5) as occurring in certain seeds 

 and green parts of plants. 



As soon as they are fully ripe the buds separate from 

 their runners and sink at once to the bottom of the water, 

 where they rest till the following spring, when they rise to 

 the surface and develop at once into young plants. It not 

 infrequently happens, however, tliat during winter some of 

 the buds become buried to a depth of an inch or more 

 under the mud at the bottom, and should this be disturbed 

 at any period during the following summer or autumn they 

 may be found still in their resting condition and showing 

 no signs of germination. 



The same result may be obtained artificially by covering 

 buds with about an inch of soil in a flowerpot, and sinking 

 the whole overhead in a vessel of water. 



In this way buds may be kept in their resting condition 

 for at least two years, the length of time during which 

 experiments have been carried on, but, as at the end of 

 that period they are still perfectly fresh and germinate at 

 once on removal from the soil, there seems no reason why 

 they should not retain their vitality very much longer. 



The utility of this capacity for continued quiescence to a 

 plant, which like Hydrocharis lives naturally in ditches 

 and shallow pools liable to prolonged periods of drought, is 

 in itself sufficiently obvious, but is rendered even more 

 striking by the very considerable degree of desiccation 

 which these buds are able to withstand while in the 

 resting condition, — they may in fact be kept air dry in an 



